Hi Olivier,
Thank you for your comments!
> On Apr 21, 2021, at 11:29 AM, Olivier Matz <olivier.m...@6wind.com> wrote:
>
> Hi Dharmik,
>
> Please see some comments below.
>
> On Mon, Apr 19, 2021 at 07:08:00PM -0500, Dharmik Thakkar wrote:
>> From: Joyce Kong <joyce.k...@arm.com>
>>
>> If cache is enabled, objects will be retrieved/put from/to cache,
>> subsequently from/to the common pool. Now the debug stats calculate
>> the objects retrieved/put from/to cache and pool together, it is
>> better to distinguish them.
>>
>> Signed-off-by: Joyce Kong <joyce.k...@arm.com>
>> Signed-off-by: Dharmik Thakkar <dharmik.thak...@arm.com>
>> Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
>> Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
>> ---
>> lib/librte_mempool/rte_mempool.c | 24 ++++++++++++++++
>> lib/librte_mempool/rte_mempool.h | 47 ++++++++++++++++++++++----------
>> 2 files changed, 57 insertions(+), 14 deletions(-)
>>
>> diff --git a/lib/librte_mempool/rte_mempool.c
>> b/lib/librte_mempool/rte_mempool.c
>> index afb1239c8d48..339f14455624 100644
>> --- a/lib/librte_mempool/rte_mempool.c
>> +++ b/lib/librte_mempool/rte_mempool.c
>> @@ -1244,6 +1244,18 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
>> for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
>> sum.put_bulk += mp->stats[lcore_id].put_bulk;
>> sum.put_objs += mp->stats[lcore_id].put_objs;
>> + sum.put_common_pool_bulk +=
>> + mp->stats[lcore_id].put_common_pool_bulk;
>> + sum.put_common_pool_objs +=
>> + mp->stats[lcore_id].put_common_pool_objs;
>> + sum.put_cache_bulk += mp->stats[lcore_id].put_cache_bulk;
>> + sum.put_cache_objs += mp->stats[lcore_id].put_cache_objs;
>> + sum.get_common_pool_bulk +=
>> + mp->stats[lcore_id].get_common_pool_bulk;
>> + sum.get_common_pool_objs +=
>> + mp->stats[lcore_id].get_common_pool_objs;
>> + sum.get_cache_bulk += mp->stats[lcore_id].get_cache_bulk;
>> + sum.get_cache_objs += mp->stats[lcore_id].get_cache_objs;
>> sum.get_success_bulk += mp->stats[lcore_id].get_success_bulk;
>> sum.get_success_objs += mp->stats[lcore_id].get_success_objs;
>> sum.get_fail_bulk += mp->stats[lcore_id].get_fail_bulk;
>> @@ -1254,6 +1266,18 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
>> fprintf(f, " stats:\n");
>> fprintf(f, " put_bulk=%"PRIu64"\n", sum.put_bulk);
>> fprintf(f, " put_objs=%"PRIu64"\n", sum.put_objs);
>> + fprintf(f, " put_common_pool_bulk=%"PRIu64"\n",
>> + sum.put_common_pool_bulk);
>> + fprintf(f, " put_common_pool_objs=%"PRIu64"\n",
>> + sum.put_common_pool_objs);
>> + fprintf(f, " put_cache_bulk=%"PRIu64"\n", sum.put_cache_bulk);
>> + fprintf(f, " put_cache_objs=%"PRIu64"\n", sum.put_cache_objs);
>> + fprintf(f, " get_common_pool_bulk=%"PRIu64"\n",
>> + sum.get_common_pool_bulk);
>> + fprintf(f, " get_common_pool_objs=%"PRIu64"\n",
>> + sum.get_common_pool_objs);
>> + fprintf(f, " get_cache_bulk=%"PRIu64"\n", sum.get_cache_bulk);
>> + fprintf(f, " get_cache_objs=%"PRIu64"\n", sum.get_cache_objs);
>> fprintf(f, " get_success_bulk=%"PRIu64"\n", sum.get_success_bulk);
>> fprintf(f, " get_success_objs=%"PRIu64"\n", sum.get_success_objs);
>> fprintf(f, " get_fail_bulk=%"PRIu64"\n", sum.get_fail_bulk);
>> diff --git a/lib/librte_mempool/rte_mempool.h
>> b/lib/librte_mempool/rte_mempool.h
>> index 848a19226149..0959f8a3f367 100644
>> --- a/lib/librte_mempool/rte_mempool.h
>> +++ b/lib/librte_mempool/rte_mempool.h
>> @@ -66,12 +66,20 @@ extern "C" {
>> * A structure that stores the mempool statistics (per-lcore).
>> */
>> struct rte_mempool_debug_stats {
>> - uint64_t put_bulk; /**< Number of puts. */
>> - uint64_t put_objs; /**< Number of objects successfully put. */
>> - uint64_t get_success_bulk; /**< Successful allocation number. */
>> - uint64_t get_success_objs; /**< Objects successfully allocated. */
>> - uint64_t get_fail_bulk; /**< Failed allocation number. */
>> - uint64_t get_fail_objs; /**< Objects that failed to be allocated. */
>> + uint64_t put_bulk; /**< Number of puts. */
>> + uint64_t put_objs; /**< Number of objects successfully
>> put. */
>> + uint64_t put_common_pool_bulk; /**< Number of bulks enqueued in
>> common pool. */
>> + uint64_t put_common_pool_objs; /**< Number of objects enqueued in
>> common pool. */
>> + uint64_t put_cache_bulk; /**< Number of bulks enqueued in
>> cache. */
>> + uint64_t put_cache_objs; /**< Number of objects enqueued in
>> cache. */
>> + uint64_t get_common_pool_bulk; /**< Number of bulks dequeued from
>> common pool. */
>> + uint64_t get_common_pool_objs; /**< Number of objects dequeued from
>> common pool. */
>> + uint64_t get_cache_bulk; /**< Number of bulks dequeued from
>> cache. */
>> + uint64_t get_cache_objs; /**< Number of objects dequeued from
>> cache. */
>> + uint64_t get_success_bulk; /**< Successful allocation number. */
>> + uint64_t get_success_objs; /**< Objects successfully allocated.
>> */
>> + uint64_t get_fail_bulk; /**< Failed allocation number. */
>> + uint64_t get_fail_objs; /**< Objects that failed to be
>> allocated. */
>
> I missed it the first time, but this changes the size of the
> rte_mempool_debug_stats structure. I think we don't care about this ABI
> breakage because this structure is only defined if
> RTE_LIBRTE_MEMPOOL_DEBUG is set. But just in case, adding Ray as Cc.
Agreed, thank you!
>
> About the field themselves, I'm not certain that there is an added value
> to have stats for cache gets and puts. My feeling is that the important
> stat to monitor is the access to common pool, because it is the one that
> highlights a possible performance impact (contention). The cache stats
> are more or less equal to "success + fail - common". Moreover, it will
> simplify the patch and avoid risks of mistakes.
>
> What do you think?
Yes, I think the cache stats can be removed.
Also, please correct me if I’m wrong; but, in my understanding,
the cache stats are equal to “success - common”. Is adding “fail” required?
>
>> /** Successful allocation number of contiguous blocks. */
>> uint64_t get_success_blks;
>> /** Failed allocation number of contiguous blocks. */
>> @@ -699,10 +707,18 @@ rte_mempool_ops_dequeue_bulk(struct rte_mempool *mp,
>> void **obj_table, unsigned n)
>> {
>> struct rte_mempool_ops *ops;
>> + int ret;
>>
>> rte_mempool_trace_ops_dequeue_bulk(mp, obj_table, n);
>> ops = rte_mempool_get_ops(mp->ops_index);
>> - return ops->dequeue(mp, obj_table, n);
>> + ret = ops->dequeue(mp, obj_table, n);
>> + if (ret == 0) {
>> + __MEMPOOL_STAT_ADD(mp, get_common_pool_bulk, 1);
>> + __MEMPOOL_STAT_ADD(mp, get_common_pool_objs, n);
>> + __MEMPOOL_STAT_ADD(mp, get_success_bulk, 1);
>> + __MEMPOOL_STAT_ADD(mp, get_success_objs, n);
>> + }
>> + return ret;
>> }
>>
>> /**
>> @@ -749,6 +765,8 @@ rte_mempool_ops_enqueue_bulk(struct rte_mempool *mp,
>> void * const *obj_table,
>> {
>> struct rte_mempool_ops *ops;
>>
>> + __MEMPOOL_STAT_ADD(mp, put_common_pool_bulk, 1);
>> + __MEMPOOL_STAT_ADD(mp, put_common_pool_objs, n);
>> rte_mempool_trace_ops_enqueue_bulk(mp, obj_table, n);
>> ops = rte_mempool_get_ops(mp->ops_index);
>> return ops->enqueue(mp, obj_table, n);
>> @@ -1297,14 +1315,18 @@ __mempool_generic_put(struct rte_mempool *mp, void *
>> const *obj_table,
>>
>> /* Add elements back into the cache */
>> rte_memcpy(&cache_objs[0], obj_table, sizeof(void *) * n);
>> -
>> cache->len += n;
>>
>> + __MEMPOOL_STAT_ADD(mp, put_cache_bulk, 1);
>> +
>> if (cache->len >= cache->flushthresh) {
>> + __MEMPOOL_STAT_ADD(mp, put_cache_objs,
>> + n - (cache->len - cache->size));
>> rte_mempool_ops_enqueue_bulk(mp, &cache->objs[cache->size],
>> cache->len - cache->size);
>> cache->len = cache->size;
>> - }
>> + } else
>> + __MEMPOOL_STAT_ADD(mp, put_cache_objs, n);
>>
>
> In case we keep cache stats, I'd add {} after the else to be consistent
> with the if().
Ack.
>
>> return;
>>
>> @@ -1438,8 +1460,8 @@ __mempool_generic_get(struct rte_mempool *mp, void
>> **obj_table,
>>
>> cache->len -= n;
>>
>> - __MEMPOOL_STAT_ADD(mp, get_success_bulk, 1);
>> - __MEMPOOL_STAT_ADD(mp, get_success_objs, n);
>> + __MEMPOOL_STAT_ADD(mp, get_cache_bulk, 1);
>> + __MEMPOOL_STAT_ADD(mp, get_cache_objs, n);
>
> In case we keep cache stats, I don't think we should remove get_success
> stats increment. Else, the success stats will never be incremented when
> retrieving objects from the cache.
>
Good catch. Thanks!
>
>>
>> return 0;
>>
>> @@ -1451,9 +1473,6 @@ __mempool_generic_get(struct rte_mempool *mp, void
>> **obj_table,
>> if (ret < 0) {
>> __MEMPOOL_STAT_ADD(mp, get_fail_bulk, 1);
>> __MEMPOOL_STAT_ADD(mp, get_fail_objs, n);
>> - } else {
>> - __MEMPOOL_STAT_ADD(mp, get_success_bulk, 1);
>> - __MEMPOOL_STAT_ADD(mp, get_success_objs, n);
>> }
>>
>> return ret;
>> --
>> 2.17.1
